self.onmessage = function(e){
    // console.log(e.data);
    //将数组中的地址资源加载出来
    let arr = e.data;
    for(let i=0; i<arr.length; i++){
      let xhr = new XMLHttpRequest(); //?
      xhr.open('get', arr[i], true); 
      xhr.responseType = 'blob'; //文件类型
      xhr.send();
      xhr.onload = function(){
        if(xhr.readyState == 4 && xhr.status == 200) {
            // console.log(xhr.response);
            self.postMessage(xhr.response);
            
        }
      }
    }
    
    

}